Imaging Antiferromagnetic Domains in Nickel-oxide Thin Films by Magneto-optical Voigt Effect

TL;DR

This paper demonstrates a novel optical method using the magneto-optical Voigt effect to directly image and study antiferromagnetic domains in NiO thin films at room temperature, enabling real-time, accessible domain visualization.

Contribution

It introduces a large Voigt rotation in NiO films that allows direct optical imaging of AFM domains with a tabletop microscope, bridging a gap in real-time AFM domain observation techniques.

Findings

Achieved up to 60 mdeg Voigt rotation in NiO films.

Visualized AFM domain patterns using a wide-field optical microscope.

Confirmed Voigt contrast originates from AFM order via XMLD-PEEM.

Abstract

Recent demonstrations of electrical detection and manipulation of antiferromagnets (AFMs) have opened new opportunities towards robust and ultrafast spintronics devices. However, it is difficult to establish the connection between the spin-transport behavior and the microscopic AFM domain states due to the lack of the real-time AFM domain imaging technique under the electric field. Here we report a significant Voigt rotation up to 60 mdeg in thin NiO(001) films at room temperature. Such large Voigt rotation allows us to directly observe AFM domains in thin-film NiO by utilizing a wide-field optical microscope. Further complementary XMLD-PEEM measurement confirms that the Voigt contrast originates from the NiO AFM order. We examine the domain pattern evolution at a wide range of temperature and with the application of external magnetic field. Comparing to large-scale-facility techniques such as the X-ray photoemission electron microscopy, the use with a wide-field, tabletop optical imaging method enables straightforward access to domain configurations of single-layer AFMs.